1. The Field of the Invention
This invention relates to devices used to improve the visibility of aircraft and avoid mid-air collisions. More particularly, the present invention relates to high intensity strobe lights used as anti-collision lights on commercial, business and military jet aircraft.
2. The Prior Art
Avoidance of collisions between aircraft is of paramount concern to those involved in the aircraft industry. While sophisticated collision avoidance systems involving radio, radar, and other sophisticated technologies are available and/or have been proposed, the primary collision avoidance system remains the vision of the pilots flying the aircraft. Pilots are taught to continually scan the observable airspace through the cockpit window. In order to improve the visibility of an aircraft, flashing anti-collision lights are included on the exterior of aircraft.
The intense, short, and attention grabbing burst of light provided by xenon gas strobe devices make such devices well suited for use as anti-collision lights. The strobe lights are configured to emit a bright flash of light at a regular interval, i.e., one second. Typical strobe lights operate by storing a large electrical charge and then discharging it through a quartz tube filled with xenon gas. The current, which can reach hundreds of amperes, ionizes the xenon gas, discharging photons and yielding a very bright flash of light.
While the xenon flash tube works well at producing a very bright and noticeable flash of light it has the disadvantage of having a relatively short operating life. The relatively short operating life of a typical xenon flash tube results from the high currents passed therethrough which cause erosion of the electrodes inside of the tube. The erosion of the electrodes requires that the flash tube eventually be replaced. The flash tubes, however, generally do not fail catastrophically, as do incandescent lamps. Rather, the light output from the flash tube slowly decreases with each firing as the metal which is eroded from the electrode is deposited on the inside of the tube. This process slowly reduces the light transmission through the tube and thus output from the flash tube decreases.
Replacing the flash tubes of anti-collision lights is a significant maintenance cost of operating an aircraft. A typical commercial airliner averages about 10.5 hours per day in flight. This amount of time in flight means that the output of a typical flash tube will be reduced to fifty percent after two to five months in use. Considering that each commercial aircraft can include anywhere from two to more than five flash tubes, and that there are over 4000 commercial airliners in the U.S. alone, and that the cost of maintenance for each flash tube equipped anti-collision light is expected to average about $1,000 per year, it will be appreciated that the cost of replacing and maintaining flash tubes in anti-collision lights is substantial. Thus, it would be a significant advance in the art to extend and improve the operating life of an aircraft anti-collision light.